Manometer



A. F. MEYER MANOMETER Filed DEC. 21, 1953 `Ian. ll, 1938.

u wm 96M o .1v. .T Fmr.. .T ,Ih Winn. w d l Amm w a7 k x N Z. Kw; A -4 mfw d .9 l 7 .oJ l. n a n n 7 mm n s ww @wcm a Sv ,v 1 2 2 Patented Jan.1l, 1938 I f UNITED STATES PATENT oFFIcE v MANoMETEn Adolph F. Meyer,Minneapolis, Minn. y Application December 21, 1933, Serial No. 703,391

10 Claims.

The present invention has relationto manometers or pressure gages.

An object of the invention is to provide a ma-l nometer or pressuregage, whichwill include a manometeror pressure-gage-indicating entitying mercury therein, and an indicator so oated' by the mercury that asubmerged part of said f indicator will always be substantiallysurrounded by mercury.

A further object is to provide a manometer or pressure gage which willinclude an indicator floated in partially submerged condition by mercurywith the submerged portion of the indicator 1 substantially surroundedbymercury under all conditions, whereby the resultant force exerted bythe mercury will at all times be suilicient to float said indicator atits natural elevation.

A further object is to provide a' manometer or pressure gage which willinclude a container with mercury therein, and an indicator oated by themercury, a portion of the indicator being submerged in the mercury andso arranged in the container that the mercury will at all timesexertsubstantially a maximum resultant force tending to float theindicator.

A further object is to provide a manometer or pressure gage which willinclude a container with mercury therein, and an indicator floated bythe mercury, a portion of the indicator being submerged in the mercuryin constantly spaced relation to the surrounding wall of the container,whereby the mercury will at all times exert substantially a maximumlifting forcejupon said indicator.

A further object is to provide a manometer or pressure gage which willinclude a container or vessel with mercury therein# a member floatedupon the mercury and having a sliding arrangement in the container orvessel, and an indicator slidably arranged in the member and oated inpartially submerged condition by the mercury.

And a further object is to provide a manometer 'or pressure gage whichwill include a container or vessel with mercury therein, .a tube oatedupon the mercury and sudabiy ntted to the can# tainer or vessel, and anindicator slidably tted to the tube, said indicator being oated by the(Cl. i3-31) mercury and including a portion thereof extending upwardlybeyond the container or vessel.

With the above objects in view, as well as others which will appear asthe specication proceeds, the invention comprises the construction, 5arrangement and combination of parts as now to be fully described andashereinafter to be specifically claimed, it being understood that thedisclosure herein is merely illustrative and intended in no way in alimiting sense, changes in details 10 of construction and arrangement ofparts being permissible so long as within the spirit of the inventionand the scope of the claims which follow.

In the accompanying drawing forming a part of this specification,

Fig. 1 is a vertical sectional view of a manometer or pressure gage madeaccording to the princlples of the invention, more especially suitablefor measuring or indicating pressure changes whenl caused by suction;

Figr 2 is Va. vertical sectional view of a manometer or pressure gagealso made according to the invention, more especially suitable formeasuring or indicating pressure changes when caused by pressure;

. Fig. 3 is a vertical sectional view of a modied i'orm of manometer orpressure gage more especially suitable for measuring or' indicatingpres--4 sure;

Fig; 4 is an enlarged horizontal sectional view, taken as on line 5 5 inFig. 1, detailing the iny dicator float and separator tube as in saidFig.'1;

Figs. 5 and 6 are diagrammatic sectional views for illustrating themanner in which rod floats can be forced against the sides of containersor vessels therefor by mercury only partially surrounding the rod oats,as hereinafter to be explained.

Referring more particularly to Figs. 1 and 4 of 40 the drawing, aU-member constituting a nonbreakable container for mercury I0, consistsof an outer, non-fragile, desirably metallic element II providing asurrounding concavity or chamber I2, and an inner, non-fragile,desirably metallic element I3 providing a preferably straight andcylindrical, upstanding passageway I4. The element I3 is open at itsupper portion, and Vincludes a port I5 at its'lower end and a valve seatI6 above the port. Said element I3 is spaced from 50 the surroundingwall of the element II except at the upper portion of the element I3,and the port I5 connects the lower portions of the concavity or chamberI2 and the passageway I4 with each other. The concavity or chamber I2 isenlarged 55 the scale 20.

at its upper portion, as indicated at I1, and the element I3 includes anannular flange/I8 desirably tightly tted into the mouth of the enlargedportion I1. A portion I9 of the element I3 projects upwardly from theannular flange I 8, which annular flange terminates flush with the upperend of the element I I. A scale 20 for the manometer or pressure gage issupported by a fixture or standard 2| which has an opening 22 tted tothe portion 4I9 ofthe element I3. The fixture or standard 2| rests uponthe annular flange I8 and the upper end of the element I I. Supportingears `23 for the manometer or pressure gage are desirably ntegralwiththe element II and have bolt receiving holes 24by means of which thedevice or instrument can be attached in upright position to a supportingstructure. A pipe 25 communicates with the enlarged portion I1 of theconcavity or chamber I2, as indicated at 26, at location below theelevation of the annular fiange I8. l

An indicator rod for the manometer or pressure gage is denoted 21. Saidrod 21 is of elongated configuration. It may desirably be circularv incross-section. The lower portion of the rod is within the passageway I4of the element I3, and the lower end of said rod is submerged in themercury, the rod being floated by the'mercury. At 28 said rod 21 isshaped to constitute a valve adapted to fit the valve seat I6 to thusclose the port I5. The upper portion of the indicator rod projectsupwardly beyond the element I3 -and its passageway I4 and lies in frontof the verti-l cally disposed scale 20. Naturally, the indicator rod 21will be of length suitable to its purpose, and the scale Awill beproperly calibrated.

A separator tube for the indicator rod is represented 23. Said tube 29is floated upon the mercury in the passageway I4 of the element I3 andis slidably fitted to said element I3 to rise and fall with the level ofthe mercury said separator tube constituting a guide for the indicatorrod. The indicator rod 21 is slidably fitted to the tube 29, as veryclearly shown in Figs. 1 and 4, and thus said tube effectually maintainssaid indicator rod and its submerged portion out of contact with thesurrounding wall of the manometer or pressure gage under all conditions.

The manometer or pressure gage as in Figs. 1 and 4 is more especiallysuitable for measuring or indicating pressure changes when caused bysuction. The arrow in the pipe 25 in Fig. 1 denotes that suction isbeing applied. The column of mercury in the concavity or chamber I2 andthe passageway I4 will stand balanced against atmospheric pressure inthe pipe 25 and the enlarged portion I1 to float the indicator rod 21 sothat its upper end is at the highest elevation on Then as suction isapplied at said pipe 25 and said enlarged portion I1, mercury will beelevated in the concavity or chamber I2 and depressed in the passagewayI4. Obviously, the indicator rod 21 and the separator tube 29 will rise'and fall withthe level of mercury in the passageway I4. A satisfactoryarrangement is to utilize a separator tube, such as 29, which is but afraction of the length of the indicator rod, such as 21.

As will be clear from Fig. l, the relative sizes and arrangement of theelements II and I3, and the amount of mercury employed, are such thatbefore the level of mercury in the enlarged portion I1 can reach theelevation of the pipe 25, 'because of suction, the valve 28 of theindicator rod will have engaged the valve .seat I6 to shut off the portI5, Thus is the possibility of passage of mercury\from the U-memberthrough the pipe 25 effectually precluded. 'I'he mouth of the enlargedportion I1 being closed by the annular flange I8, the mercury cannototherwise pass from the concavity or chamber I2 save through thepassageway I4. To preclude the possibility of the travel of mercuryupwardly out of the portion I9 of the passageway I4, as by a surging atthe` pipe 25 caused by back pressure, the relative sizes and arrangementof the elements II and I3, and the amountof mercury employed, are suchthat within `the range of the manometer or pressure gage,V the mercurycannot reach any dangerous level in the passageway I4. That is to say,the device is so constructed that the mercury when under atinosphericpressure in the enlarged portion I1 is at elevation considerably belowthe upper end of the passageway, so that should the pressure in saidenlarged portion I1 become considerably above atmospheric, the level ofmercury would not yet 'sages of manometers or pressure gages. In thedevice or instrument of the invention, the liquid .employed as a mediumbalanced against pressure to be measured, ordinarily mercury, will bepermanently housed in the non-fragile container, which in effect willconstitute a non-breakable seal for the mercury.

In,Fig. 2 of the drawing, a U-member constituting a non-breakablecontainer `for mercury I0 consists of an outer, non-fragile, desirablymetallic element II' providing a. surrounding concavity or chamber I2',and an inner, nonfragile, desirably metallic element I3' providing apreferably straight and cylindrical, upstanding passageway I4. Theelement I3' is constructed precisely like the element I3 and includes aport I5 and a valve seat I6 above the port. Said element I3 is mountedin the element I I in the same manner as above described, and the portI5' functions in the same manner as does the port I5. 'Ihe concavity orchamber I2' is enlarged for the greater portion of its length, as

indicated at I1', and the element I3 includes an annular flange I8'fitted to the element Il' in the manner as set forth in connection withthe element I3. A- portion I9 of the element I3' projects upwardly fromthe annular ange I8', as before described. A scale 20 is upon afixtureor standard 2l' supported by its opening 22' as hereinbefore appears.Ears 23' with holes 24' are for the same purpose as the equivalent partsshown in Fig. 1. A pipe 25' communicates with the upper part of theenlarged portion I1', as indicated at 26', at location below the annularflange I8.

An indicator rod 21' is equivalent to the indicator ro'd 21, said rod21' including a valve 28' to fit the valve seat I5', and being slidablyfitted to a separator tube 29 floated upon the mercury inthe passagewayI 4 and slidably tted to the element I3'. In short, the elements I3',I4', I5', I6', 21', 28 and 29 are equivalentto the elements I3, I4, I5,I6, 21, 2B and 29 before described, and similarly function.

The manometer or pressure gage as in Fig. 2

.f is more especiallyfsuitable tormea/suring or indieating pressurechanges when caused by pressure. The arrow in the pipe 25' in Fig. 2denotes that pressure is being applied. The` column of mercury in theconcavity or chamber- 12' and the passageway I4' will stand balancedagainst atmospheric pressure in-the pipe 2,5' and the ern- .largedportion I1' to oat the indicator Arod21' so that its upper end`is at thelowest elevation on the scale 20. IThen as pressure is applied at 'saidpipe 25' and said enlarged portion I1', mer- As will be clear from Fig.2, the relative sizes and arrangement of the elements II and I3',- andthe amount of mercury employed, are such that before the level of themercury in the enlarged portion I1' can reach the elevation of the pipe25 because of surging causing back pressure, the valve 28' of theindicator rod will have engaged the valve seat I6' to shut off the portI5', so that the possibility of passage of mercury from the U-memberthrough the ,pipe 25' is effectually precluded, as already set forth.'

The mouth of the enlarged portion I1' being closed by the annular angeI8', the mercury cannot otherwise pass from the concavity or chamber I2'save through the passageway I4'. To preclude the possibility of thetravel of mercury upwardly out of the portion I9' of the passageway I4by pressure at the pipe 25' and the enlarged portion I1', the relativesizes and arrangement of the elements II' and I3', and the amount ofmercury employed, are such that within the range of the manometer orpressure gage, the mercury cannot reach any dangerous A.

level in the passageway I 4'. That is, the mercury when under themaximum pressure intended to exist in the enlarged portion I1 is atelevation considerablyl below the upper end of the passageway I4', sothat should the pressure in vsaid enlarged portion I1' becomeconsiderably above said maximum pressure intended, the level of mercurywould not yet reach overflowing elevation in said passageway I4'. Thus,the non-fragile container of Fig. 2 completely houses the whole of thecolumn of mercury throughout the range of the manometer or pressuregage, in the same general manner and with the same result as describedin connection with Fig. 1.

It Will be noted that the scales 20 and 20'V of Figs. 1 and 2 haveunequal division lines. The

division of the scale will of course depend upon the working conditions.

the element II", is shown shaped at 30 to. make provisionl for saidequal division lines. Aside from the features just mentioned, the deviceor instrument of Fig. 3 is the same as that of Fig. 2, except that anannular ilange |88, equivalent to the annular ange I8', includesaninternal circular shoulder 3| against which an upper base 32 of aseparator tube 29a, equivalent to the tube 29', is adapted to engagewhen said separator tube 29a reaches its highest elevation. Also, theupper base 32 includes an opening 33 for an indicator rod 21B,equivalent to the rod 21', and a valve seat 34 beneath the opening, andsaid indicator rod 21has an enlarged portion 35 slidably fitted .to theseparator tube 29S. The upper en'd of the enlarged portion 35 is shaped,

4suitable for measuring or indicating pressure changes when caused bypressure. 'I'he arrow in the pipe 25 in Fig. 3 denotes that pressure` isbeing applied. The column of mercury in the concavity Qr chamber I2* andthe passageway I4* will stand balanced against atmospheric presf Isure`in thevpipe 25? and the enlarged portion I1n to oat the indicatorrod 21s so that its upper end is at the lowest elevation on the scale 20carried .by the xture or standard 2I. As pressure is applied at saidpipe 25* and said enlarged portion |15, mercury I* .will be depressedin' the chamber I 2* having the shaped portion 3U and elevated in thepassageway- I4. The indicator Vrod 21 and the separator tube 29'l willrise and fall with the level of mercury in the passageway |43.

As will be clear from Fig. 3, the relative sizes and arrangement of theelements IIa and I3, and the amount of mercury employed,` are such thatbefore the level of the mercury in the enlarged portion I1a can reachthe elevation of the pipe 25 because of surging causing back pressureyin the pipe 25B and the portion I1, the valve 28a of the indicator rod21 will have engaged the valve seat I6"l toshut o the port I5, so thatthe possibility of passage of mercury from the U-member through the pipe25B is effectually precluded. The mouth of the enlarged portion Ilabeing closed by the annular ange |89, the mercury cannot otherwise passfrom the concavity or chamber I2 save through the passageway I4, 'I'hemercury when under pressure greater than the maximum pressure intendedto exist in the enlarged portion I1 will cause the upper base 32 of theseparator tube 29B to engage ,the circular shoulder 3l and the valve 36to engage the valve seat 34, to thus preclude the possibility of thetravel of mercury upwardly out ofY the portion I9a of the passageway I4aby pressure at the pipe 25 and the enlarged portion I1, Evidently, thenon-fragile container of Fig. 3 completely houses the whole of thecolumn of mercury throughout the range of the manometer or pressuregage, and constitutes a non-breakable seal for the 'mercury In Figs. and6 of the drawing -there is disclosed two separate mercury containingvessels, denoted 42 and 43, respectively, each with a rod float,indicated 44 and 45, respectively, the rod floats being suggested asindicator rods, such as 21, 21', and 21B, for manometers or pressuregages employing mercury as the medium balanced against pressure to bemeasured. But it has been discovered that an indicator rod so floated onmercury and guided by the surrounding wall of the containing vessel forthe mercury is not a satrisfactory arrangement, because there is alwaystendency for the mercury to hold the indicator rod against the side ofthe vessel, when for any reason the indicator rod becomes depressed inthe mercury, and thus cause the rod to become stuck. 'I'he reason forthe sticking of the indicator rod is that when the rod is forced downinto the mercury, the heavy mercury with its high surface tensionforces-the. rod. against the,

account of the high surface tension of mercury,

and the repulsion between the mercury and the material of the containerand the rod, this area devoid of mercury is of substantial width.Speaking generally, when the rod float and the containing vessel are ofnearly the same size, 'there is greater tendency toward sticking of therod. The tendency for the oat to stick after having been forced downinto the mercury in the vessel is not only related to the relative areasof the float and vessel, but also to the diameter of the iioat, andthedepth to which the float is forced into the mercury. The force pressingthe iioat against the wall of the vessel is proportional to the depth ofimmersion and the Width of the void space back of the rod. The frictioncoeiiicient, of y course, must also be considered.

More specifically, a small diameter rod, such as 45, in a vessel, suchas 43, when placed against the side of the vessel will beheld, as shownin Fig. 6, by a force proportional to the depth of submergence and thewidth of the space,'repre sented 46, back of the rod not occupied bymercury. As disclosed in said Fig. 6, the repellent -action of themercury with respect to the wall of the vessel and rod is such that theWidth of the void space 46 back of the rod is about equal to thediameter of the rod, Whereas in the case of the rod 44 in the vessel 42of Fig. 5, the Width of the void space 41 back of said rod 44 isaboutequal to the width of the void space 46 back of the rod 45, the rod 44and vessel 42 being of about the same relative diameters as are the rod45 and the vessel 43. Therefore, for a given submergence, the forcetending to hold the rod 45 against the side of the vessel 43 isrelatively much larger than the force tending to hold the rod 44 againstthe vessel 42. On the other hand, the force tending to iioat the rod 44upw-ardly, being proportional to the square of the diameter, isrelatively much greater than is the force tend. ing to float the rod 45upwardly. It thus develops that difficulties are encountered with rodsas in Figs. 5 and 6, particularly those for use with small-scale,low-cost apparatus employing fluid such as mercury. It is a readilydemonstrable fact that when a rod of even relatively light material andof, say, one-eighth or one-quarter inch diameter and six inches lengthis floated on mercury in a guiding vessel for the rod, and is forceddown into the mercury for a distance of, say, two inches. the rod willnot oat upward again, but will be held quite 'rigidly against the sideof the vessel, as in Figs. 8 and 9, by the pressure of the mercuryagainst the rod.

The keeping of the rod away from the side or wall of the guiding vesseltherefor, as by em ployment of a separator tube, such as 29, 29', or29a, so that the mercury will surround the rod when forced down in themercury, will cause a depressed rod to quickly rise to its naturalelevation in the mercury when released. As will be evident, whenever therod is forced down into the mercury, the separator tube is forcedupwardly by the displacement of mercury, permitting the mercury tocompletely surround the rod :and to quickly force the rod upwardly whenreleased. 'I'here is no tendency for the rod to become locked by mercurygetting between the separator tube and rod, because any displacement ofmercury readily elevates the tube which is relatively light and alwaysfollows the mercury level. Also, there is no tendency for the mercury tolock the separator tube in the vessel against the side or wall thereofwhile said tube iioats upon the surface of' the mercury. In addition,should there be tendenside of both the rod and the tube, and such abalancing is evidently not even a remote possibility. An indicator rodfloated in partially submerged condition on mercury as in Figs. 1, 2 and3, so

that the submerged portion of the rod will be surrounded by mercuryunder all conditions, insures that the resultant force' exerted by themercury will at all times be the maximum resultant force tending tofloat the rod.

What I claim is:

1. A manometer comprising a vessel adapted to receive a liquid to bebalanced against pressure to be measured, amember adapted to be iioatedupon said liquid to have a sliding arrangecluding a portion thereofextending upwardly.

3. Amanometer comprising a vessel adapted to receive mercury to bebalanced against pressure to be measured, a tube adapted to be oatedupon said mercury and slidably guided by said vessel, and a relativelylong oat adapted to-be surrounded by said tube and supported by saidercury, said float being adapted to indicate the level of mercury insaid vessel.

4. A manometer comprising a vessel for receiving a liquid adapted to bebalanced against pressure-to be measured, a tube adapted to be floatedby said liquid and'guided by said vessel, and a rod oatadapted to beloosely surrounded by said tube and guided thereby, said rod float beingadapted to be supported by said liquid to indicate the level thereof insaid vessel.

5. A manometer comprising a vessel having a liquid therein adapted to bebalanced against pressure to be measured, a relatively short,holrelatively short, hollow tube surrounding said indicator float inloose-fitting relation thereto.

6. A manometer comprising a vessel adapted to yreceive a liquid to bebalanced against pressur-e to be measured, and an indicator and anelongated guide therefor iioated by said liquid, said indicator andguide being adapted to have movement relatively to each other.

7. A manometer comprising a vessel adapted to receive a liquid to bebalanced against pressure to .be measured, and an indicator and anelongated guide therefor floated by said liquid, said guide spacing saidindicator from the wall of said vessel, and said indicator and guidebeing adapted to have movement relatively to each other. I

8. A manometer comprising a vessel adapted to receivea liquid to bebalanced against pressure to be measured, and an indicator andanelongated guide therefor floated by said liquid, said guide spacing saidindicatorv from the wall of said vessel, said indicator projectingupwardly of said vessel, and said indicator and guide being adapted tohave movement relatively to each other.

9. A manometer comprising a vessel adapted to receive a liquid to bebalanced against pressure to be measured, an indicator oated by saidliquid and extending upwardly in said vessel, said indicator beingpartial-ly submerged in said liquid, and elongated means floated by saidliquid for causing the submerged portion of said indicator to be atleast partially surrounded by liquid between the indicator and the wallof the vessel,

said indicator and said means being adapted to have movement relativelyto each other.

10. A manometer comprising a. vessel adapted to receive a liquid to bebalanced against pressure to be measured, an elongated member adapted tobe floated by said liquid and guided by said vessel, and a rod iioatadapted to be guided by said member, said rod oat being adapted to besupported by said liquid to indicate the level thereof in said vessel,and said rod iioat and member being adapted to have movement relativelyto each other.

ADOLPH F. MEYER.

